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[DllImport("iphlpapi.dll", SetLastError=true)]

Declare Function AddIPAddress Lib "iphlpapi.dll" (TODO) As TODO

Alternative Managed API:

Do you know one? Please contribute it!

Please add some!

Sample Code:

Please add some!

  public class MyClass

      [DllImport("iphlpapi.dll", EntryPoint = "AddIPAddress", SetLastError = true)]

    public MyClass()

      public void AddIPAddress(String IPAddress, String SubnetMask, int ifIndex)

        UInt32 Result =  MyAddIPAddress((uint)IPAdd.Address,

[DllImport("iphlpapi.dll", SetLastError=true)]

static extern int EnableRouter(IntPtr pHandle, ref System.Threading.NativeOverlapped pOverlapped);

    <DllImport("iphlpapi.dll", CharSet:=CharSet.Ansi)>

    Public Shared Function EnableRouter(pHandle As IntPtr, ByRef pOverlapped As OVERLAPPED) As Integer

Alternative Managed API:

Do you know one? Please contribute it!

Please add some!

Sample Code:

VB.NET Example

    <StructLayout(LayoutKind.Explicit, Size:=20)>

    Public Structure OVERLAPPED

    <FieldOffset(0)>

    Public Internal As UInt32

    <FieldOffset(4)>

    Public InternalHigh As UInt32

    <FieldOffset(8)>

    Public Offset As UInt32

    <FieldOffset(12)>

    Public OffsetHigh As UInt32

    <FieldOffset(8)>

    Public Pointer As IntPtr

    <FieldOffset(16)>

    Public hEvent As IntPtr

    <DllImport("iphlpapi.dll", CharSet:=CharSet.Ansi)>

    Public Shared Function EnableRouter(pHandle As IntPtr, ByRef pOverlapped As OVERLAPPED) As Integer

    <DllImport("kernel32.dll", EntryPoint:="CreateEventA", CharSet:=CharSet.Unicode)>

    Public Shared Function CreateEvent(lpEventAttributes As IntPtr, ByVal bManualReset As Boolean, ByVal bInitialState As Boolean, ByVal lpName As String) As IntPtr

    Private pOverlapped As OVERLAPPED ' <- Important! This should also be used when calling UnenableRouter() API Function.

    Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click

    ' OVERLAPPED strucutre fields can be NULLED except hEvent field.

    pOverlapped.hEvent = CreateEvent(IntPtr.Zero, False, False, "enablerouter")

    Dim RetVal As Integer = EnableRouter(IntPtr.Zero, pOverlapped)

    If RetVal = ERROR_IO_PENDING Then

        Console.WriteLine("Success!")

    Else

        Dim errorMessage As String = New Win32Exception(RetVal).Message

        Console.WriteLine("Error {0}", errorMessage)

    [StructLayout(LayoutKind.Sequential, CharSet=CharSet.Ansi)]

        [MarshalAs(UnmanagedType.ByValTStr, SizeConst=MAX_HOSTNAME_LEN + 4)]

        public string HostName;

        [MarshalAs(UnmanagedType.ByValTStr, SizeConst=MAX_HOSTNAME_LEN + 4)]

        public string DomainName;

        public IntPtr CurrentDnsServer;

        public IP_ADDR_STRING DnsServerList;

        public uint NodeType;

        [MarshalAs(UnmanagedType.ByValTStr, SizeConst=MAX_SCOPE_ID_LEN + 4)]

        public string ScopeId;

        public uint EnableRouting;

        public uint EnableProxy;

        public uint EnableDns;

Declare Function FIXED_INFO Lib "iphlpapi.dll" (TODO) As TODO

Alternative Managed API:

Do you know one? Please contribute it!

Please add some!

Sample Code:

Please add some!

[DllImport("iphlpapi.dll", SetLastError=true)]

Declare Function GetAdapterIndex Lib "iphlpapi.dll" (TODO) As TODO

Alternative Managed API:

Do you know one? Please contribute it!

Please add some!

Sample Code:

Please add some!

[DllImport("iphlpapi.dll")]

private static extern ERROR GetAdaptersAddresses(uint Family, uint Flags, IntPtr Reserved, IntPtr pAdapterAddresses, ref uint pOutBufLen);

Alternative Managed API:

Some, but not, all the information provided by the P/Invoke are available from the managed System.Net.NetworkInformation.NetworkInterface (http://msdn.microsoft.com/en-us/library/system.net.networkinformation.networkinterface.aspx) class.

Sample Code:

    public class IPIntertop

    public enum FAMILY : uint

        /// Unpecified. Includes both IPv4 and IPv4

    public enum FLAGS : uint

        GAA_FLAG_SKIP_UNICAST = 0x0001,

        GAA_FLAG_SKIP_ANYCAST = 0x0002,

        GAA_FLAG_SKIP_MULTICAST = 0x0004,

        GAA_FLAG_SKIP_DNS_SERVER = 0x0008,

        GAA_FLAG_INCLUDE_PREFIX = 0x0010,

        GAA_FLAG_SKIP_FRIENDLY_NAME = 0x0020

    public enum ERROR : uint

        ERROR_BUFFER_OVERFLOW = 111,

        ERROR_INVALID_PARAMETER = 87

    public enum IF_OPER_STATUS : uint

        IfOperStatusLowerLayerDown,

    public enum IF_TYPE : uint

        IF_TYPE_OTHER = 1,   // None of the below

        IF_TYPE_REGULAR_1822 = 2,

        IF_TYPE_STARLAN = 11,

        IF_TYPE_HYPERCHANNEL = 14,

        IF_TYPE_LAP_B = 16,

        IF_TYPE_SDLC = 17,

        IF_TYPE_E1 = 19,  // Obsolete; see DS1-MIB

        IF_TYPE_PROP_POINT2POINT_SERIAL = 22,  // proprietary serial

        IF_TYPE_SOFTWARE_LOOPBACK = 24,

        IF_TYPE_EON = 25,  // CLNP over IP

        IF_TYPE_SLIP = 28,  // Generic Slip

        IF_TYPE_ULTRA = 29,  // ULTRA Technologies

        IF_TYPE_FRAMERELAY = 32,  // DTE only

        IF_TYPE_PARA = 34,  // Parallel port

        IF_TYPE_ARCNET_PLUS = 36,

        IF_TYPE_ATM = 37,  // ATM cells

        IF_TYPE_X25_PLE = 40,

        IF_TYPE_ISO88022_LLC = 41,

        IF_TYPE_LOCALTALK = 42,

        IF_TYPE_FRAMERELAY_SERVICE = 44,  // FRNETSERV-MIB

        IF_TYPE_AAL5 = 49,  // AAL5 over ATM

        IF_TYPE_PROP_VIRTUAL = 53,  // Proprietary virtual/internal

        IF_TYPE_PROP_MULTIPLEXOR = 54,  // Proprietary multiplexing

        IF_TYPE_FIBRECHANNEL = 56,

        IF_TYPE_FRAMERELAY_INTERCONNECT = 58,  // Obsolete, use 32 or 44

        IF_TYPE_AFLANE_8023 = 59,  // ATM Emulated LAN for 802.3

        IF_TYPE_AFLANE_8025 = 60,  // ATM Emulated LAN for 802.5

        IF_TYPE_CCTEMUL = 61,  // ATM Emulated circuit

        IF_TYPE_G703_2MB = 67,  // Obsolete; see DS1-MIB

        IF_TYPE_QLLC = 68,  // SNA QLLC

        IF_TYPE_CHANNEL = 70,

        IF_TYPE_IBM370PARCHAN = 72,  // IBM System 360/370 OEMI Channel

        IF_TYPE_DLSW = 74,  // Data Link Switching

        IF_TYPE_LAP_D = 77,  // Link Access Protocol D

        IF_TYPE_ATM_LOGICAL = 80,  // ATM Logical Port

        IF_TYPE_DS0 = 81,  // Digital Signal Level 0

        IF_TYPE_DS0_BUNDLE = 82,  // Group of ds0s on the same ds1

        IF_TYPE_BSC = 83,  // Bisynchronous Protocol

        IF_TYPE_ASYNC = 84,  // Asynchronous Protocol

        IF_TYPE_EPLRS = 87,  // Ext Pos Loc Report Sys

        IF_TYPE_ARAP = 88,  // Appletalk Remote Access Protocol

        IF_TYPE_PROP_CNLS = 89,  // Proprietary Connectionless Proto

        IF_TYPE_HOSTPAD = 90,  // CCITT-ITU X.29 PAD Protocol

        IF_TYPE_TERMPAD = 91,  // CCITT-ITU X.3 PAD Facility

        IF_TYPE_FRAMERELAY_MPI = 92,  // Multiproto Interconnect over FR

        IF_TYPE_ADSL = 94,  // Asymmetric Digital Subscrbr Loop

        IF_TYPE_RADSL = 95,  // Rate-Adapt Digital Subscrbr Loop

        IF_TYPE_SDSL = 96,  // Symmetric Digital Subscriber Loop

        IF_TYPE_VDSL = 97,  // Very H-Speed Digital Subscrb Loop

        IF_TYPE_VOICE_ENCAP = 103,  // Voice encapsulation

        IF_TYPE_VOICE_OVERIP = 104,  // Voice over IP encapsulation

        IF_TYPE_PPPMULTILINKBUNDLE = 108,  // PPP Multilink Bundle

        IF_TYPE_IPOVER_CDLC = 109,  // IBM ipOverCdlc

        IF_TYPE_IPOVER_CLAW = 110,  // IBM Common Link Access to Workstn

        IF_TYPE_VIRTUALIPADDRESS = 112,  // IBM VIPA

        IF_TYPE_MPC = 113,  // IBM multi-proto channel support

        IF_TYPE_TDLC = 116,  // IBM twinaxial data link control

        IF_TYPE_HDLC = 118,

        IF_TYPE_LAP_F = 119,

        IF_TYPE_X25_MLP = 121,  // Multi-Link Protocol

        IF_TYPE_TRANSPHDLC = 123,

        IF_TYPE_INTERLEAVE = 124,  // Interleave channel

        IF_TYPE_FAST = 125,  // Fast channel

        IF_TYPE_DOCSCABLE_MACLAYER = 127,  // CATV Mac Layer

        IF_TYPE_DOCSCABLE_DOWNSTREAM = 128,  // CATV Downstream interface

        IF_TYPE_DOCSCABLE_UPSTREAM = 129,  // CATV Upstream interface

        IF_TYPE_A12MPPSWITCH = 130,  // Avalon Parallel Processor

        IF_TYPE_TUNNEL = 131,  // Encapsulation interface

        IF_TYPE_CES = 133,  // Circuit Emulation Service

        IF_TYPE_L2_VLAN = 135,  // Layer 2 Virtual LAN using 802.1Q

        IF_TYPE_L3_IPVLAN = 136,  // Layer 3 Virtual LAN using IP

        IF_TYPE_L3_IPXVLAN = 137,  // Layer 3 Virtual LAN using IPX

        IF_TYPE_DIGITALPOWERLINE = 138,  // IP over Power Lines

        IF_TYPE_MEDIAMAILOVERIP = 139,  // Multimedia Mail over IP

        IF_TYPE_MSDSL = 143,  // Multi-rate Symmetric DSL

        IF_TYPE_IEEE1394 = 144,  // IEEE1394 High Perf Serial Bus

        IF_TYPE_RECEIVE_ONLY = 145 // TV adapter type

    public enum IP_SUFFIX_ORIGIN : uint

        IpSuffixOriginManual,

        IpSuffixOriginWellKnown,

        IpSuffixOriginLinkLayerAddress,

    public enum IP_PREFIX_ORIGIN : uint

        IpPrefixOriginManual,

        IpPrefixOriginWellKnown,

    public enum IP_DAD_STATE : uint

        /// IpDadStateInvalid -> 0

        IpDadStateInvalid = 0,

        IpDadStateDuplicate,

    public enum NET_IF_CONNECTION_TYPE : uint

    public enum TUNNEL_TYPE : uint {

        TUNNEL_TYPE_NONE = 0,

        TUNNEL_TYPE_OTHER = 1,

        TUNNEL_TYPE_DIRECT = 2,

        TUNNEL_TYPE_6TO4 = 11,

        TUNNEL_TYPE_ISATAP = 13,

        TUNNEL_TYPE_TEREDO = 14,

        TUNNEL_TYPE_IPHTTPS = 15

    [StructLayout(LayoutKind.Sequential)]

    public struct GUID {

        [MarshalAs(UnmanagedType.ByValArray, SizeConst = 8)]

    private const int MAX_ADAPTER_ADDRESS_LENGTH = 8;

    private const int MAX_ADAPTER_NAME_LENGTH = 256;

    private const int MAX_DHCPV6_DUID_LENGTH = 130;

    [StructLayout(LayoutKind.Sequential)]

    public struct SOCKADDR

        public ushort sa_family;

        [MarshalAs(UnmanagedType.ByValArray, SizeConst = 14)]

        public byte[] sa_data;

    [StructLayout(LayoutKind.Sequential)]

    public struct SOCKET_ADDRESS

        public IntPtr lpSockAddr;

        public int iSockaddrLength;

    [StructLayout(LayoutKind.Sequential)]

    public struct IP_ADAPTER_UNICAST_ADDRESS

        public UInt64 Alignment;

        public IntPtr Next;

        public SOCKET_ADDRESS Address;

        public IP_PREFIX_ORIGIN PrefixOrigin;

        public IP_SUFFIX_ORIGIN SuffixOrigin;

        public IP_DAD_STATE DadState;

        public uint ValidLifetime;

        public uint PreferredLifetime;

        public uint LeaseLifetime;

    [StructLayout(LayoutKind.Sequential)]

    public struct IP_ADAPTER_ADDRESSES

        public UInt64 Alignment;

        public IntPtr Next;

        public IntPtr AdapterName;

        public IntPtr FirstUnicastAddress;

        public IntPtr FirstAnycastAddress;

        public IntPtr FirstMulticastAddress;

        public IntPtr FirstDnsServerAddress;

        [MarshalAs(UnmanagedType.LPWStr)]

        public string DnsSuffix;

        [System.Runtime.InteropServices.MarshalAs(UnmanagedType.LPWStr)]

        public string Description;

        [System.Runtime.InteropServices.MarshalAs(UnmanagedType.LPWStr)]

        public string FriendlyName;

        [MarshalAs(UnmanagedType.ByValArray, SizeConst = MAX_ADAPTER_ADDRESS_LENGTH)]

        public byte[] PhysicalAddress;

        public uint PhysicalAddressLength;

        public uint Flags;

        public uint Mtu;

        public IF_TYPE IfType;

        public IF_OPER_STATUS OperStatus;

        [MarshalAs(UnmanagedType.ByValArray, SizeConst = 16)]

        public uint[] ZoneIndices;

        public IntPtr FirstPrefix;

        // May need to be removed on Windows versions below Vista to work properly (?)

        public UInt64 TrasmitLinkSpeed;

        public UInt64 ReceiveLinkSpeed;

        public IntPtr FirstWinsServerAddress;

        public IntPtr FirstGatewayAddress;

        public uint Ipv4Metric;

        public uint Ipv6Metric;

        public UInt64 Luid;

        public SOCKET_ADDRESS Dhcpv4Server;

        public uint CompartmentId;

        public GUID NetworkGuid;

        public NET_IF_CONNECTION_TYPE ConnectionType;

        public TUNNEL_TYPE TunnelType;

        public SOCKET_ADDRESS Dhcpv6Server;

        [MarshalAs(UnmanagedType.ByValArray, SizeConst = MAX_DHCPV6_DUID_LENGTH)]

        public byte[] Dhcpv6ClientDuid;

        public uint Dhcpv6ClientDuidLength;

        public uint Dhcpv6Iaid;

        public uint FirstDnsSuffix;

    [DllImport("iphlpapi.dll")]

    private static extern ERROR GetAdaptersAddresses(uint Family, uint Flags, IntPtr Reserved, IntPtr pAdapterAddresses, ref uint pOutBufLen);

    public static string MarshalString(IntPtr text)

        // !!!: This should only be used with IP_ADAPTER_ADDRESSES.AdapterName since it can't be marshalled automatically

        byte[] cName = new byte[MAX_ADAPTER_NAME_LENGTH];

        Marshal.Copy(text, cName, 0, MAX_ADAPTER_NAME_LENGTH);

        string name = Encoding.ASCII.GetString(cName, 0, MAX_ADAPTER_NAME_LENGTH);

    public static IList<IP_ADAPTER_ADDRESSES> GetIPAdapters(FAMILY family)

        List<IP_ADAPTER_ADDRESSES> adapters = new List<IP_ADAPTER_ADDRESSES>();

        uint outBufLen = 0;

        ERROR err = GetAdaptersAddresses((uint)family, (uint)0, IntPtr.Zero, IntPtr.Zero, ref outBufLen);

        if (ERROR.ERROR_BUFFER_OVERFLOW == err)

        IntPtr pAdapterAddresses = Marshal.AllocHGlobal((int)outBufLen);

            err = GetAdaptersAddresses((uint)FAMILY.AF_INET, (uint)0, IntPtr.Zero, pAdapterAddresses, ref outBufLen);

            while (IntPtr.Zero != currPtr)

                IP_ADAPTER_ADDRESSES addr = (IP_ADAPTER_ADDRESSES)Marshal.PtrToStructure(currPtr, typeof(IP_ADAPTER_ADDRESSES));

        finally

            Marshal.FreeHGlobal(pAdapterAddresses);

    public static IList<IPAddress> GetIPAddresses(FAMILY family)

        List<IPAddress> addresses = new List<IPAddress>();

        foreach (IP_ADAPTER_ADDRESSES addr in GetIPAdapters(family)) {

            IP_ADAPTER_UNICAST_ADDRESS unicastAddr = (IP_ADAPTER_UNICAST_ADDRESS)Marshal.PtrToStructure(addr.FirstUnicastAddress, typeof(IP_ADAPTER_UNICAST_ADDRESS));

            if (IntPtr.Zero != unicastAddr.Address.lpSockAddr)

            SOCKADDR socketAddr = (SOCKADDR)Marshal.PtrToStructure(unicastAddr.Address.lpSockAddr, typeof(SOCKADDR));

AdapterName is an ASCII string, I was unable to Marshal automatically, you can use this code to get it:

byte[] cName = new byte[MAX_ADAPTER_NAME_LENGTH];

Marshal.Copy(addr.AdapterName, cName, 0, MAX_ADAPTER_NAME_LENGTH);

string name = Encoding.ASCII.GetString(cName, 0, MAX_ADAPTER_NAME_LENGTH);

Please add some!

[DllImport("iphlpapi.dll", CharSet=CharSet.Ansi)]

public static extern int GetAdaptersInfo(IntPtr pAdapterInfo, ref Int64 pBufOutLen);

<DllImport("iphlpapi.dll", EntryPoint:="GetAdaptersInfo", CharSet:=CharSet.Ansi)> _

     ByVal pAdapterInfo As IntPtr, _

     ByRef pBufOutLen As UInt64) As Int32

Sample Code:

Public Sub GetAdapters()

     Dim structSize As Int32 = Marshal.SizeOf(GetType(IP_ADAPTER_INFO))

     Dim pArray As IntPtr = Marshal.AllocHGlobal(structSize)

     Dim len As UInt64 = Convert.ToUInt64(structSize)

     Dim ret As Int32 = GetAdaptersInfo(pArray, len)

     ' Buffer was too small, reallocate the correct size for the buffer.

     pArray = Marshal.ReAllocHGlobal(pArray, New IntPtr(Convert.ToInt64(len)))

     ret = GetAdaptersInfo(pArray, len)

     ' Call succeeded

         Dim Entry As IP_ADAPTER_INFO = CType(Marshal.PtrToStructure(pEntry, GetType(IP_ADAPTER_INFO)), IP_ADAPTER_INFO)

     Loop Until IntPtr.op_Equality(pEntry, IntPtr.Zero)

     Marshal.FreeHGlobal(pArray)

C# Sample Code:

        const int MAX_ADAPTER_DESCRIPTION_LENGTH = 128;

        const int ERROR_BUFFER_OVERFLOW = 111;

        const int MAX_ADAPTER_NAME_LENGTH = 256;

        const int MAX_ADAPTER_ADDRESS_LENGTH = 8;

        const int MIB_IF_TYPE_LOOPBACK = 24;

        const int MIB_IF_TYPE_SLIP = 28;

public static void GetAdapters()

   long structSize = Marshal.SizeOf( typeof( IP_ADAPTER_INFO ) );

   IntPtr pArray = Marshal.AllocHGlobal( new IntPtr(structSize) );

   if (ret == ERROR_BUFFER_OVERFLOW ) // ERROR_BUFFER_OVERFLOW == 111

     // Buffer was too small, reallocate the correct size for the buffer.

     pArray = Marshal.ReAllocHGlobal( pArray, new IntPtr (structSize) );

     // Call Succeeded

       IP_ADAPTER_INFO entry = (IP_ADAPTER_INFO)Marshal.PtrToStructure( pEntry, typeof( IP_ADAPTER_INFO ));

       Console.WriteLine("\n");

       Console.WriteLine( "Index: {0}", entry.Index.ToString() );

         case MIB_IF_TYPE_LOOPBACK  : tmpString = "Loopback"; break;

         case MIB_IF_TYPE_SLIP      : tmpString = "Slip"; break;

         default                    : tmpString = "Other/Unknown"; break;

       Console.WriteLine( "Adapter Type: {0}", tmpString );

       Console.WriteLine( "Name: {0}", entry.AdapterName );

       Console.WriteLine( "Desc: {0}\n", entry.AdapterDescription );

       Console.WriteLine( "DHCP Enabled: {0}", ( entry.DhcpEnabled == 1 ) ? "Yes" : "No" );

       if (entry.DhcpEnabled == 1)

         Console.WriteLine( "DHCP Server : {0}", entry.DhcpServer.IpAddress.Address );

         // Lease Obtained (convert from "time_t" to C# DateTime)

         DateTime pdatDate = new DateTime(1970, 1, 1).AddSeconds( entry.LeaseObtained ).ToLocalTime();

         Console.WriteLine( "Lease Obtained: {0}", pdatDate.ToString() );

         // Lease Expires (convert from "time_t" to C# DateTime)

         pdatDate = new DateTime(1970, 1, 1).AddSeconds( entry.LeaseExpires ).ToLocalTime();

         Console.WriteLine( "Lease Expires : {0}\n", pdatDate.ToString() );

       } // if DhcpEnabled

       Console.WriteLine( "IP Address     : {0}", entry.IpAddressList.IpAddress.Address );

       Console.WriteLine( "Subnet Mask    : {0}", entry.IpAddressList.IpMask.Address );

       Console.WriteLine( "Default Gateway: {0}", entry.GatewayList.IpAddress.Address );

       for (int i = 0; i < entry.AddressLength - 1; i++)

       Console.WriteLine( "MAC Address    : {0}{1:X2}\n", tmpString, entry.Address[entry.AddressLength - 1] );

       Console.WriteLine( "Has WINS: {0}", entry.HaveWins ? "Yes" : "No" );

         Console.WriteLine( "Primary WINS Server  : {0}", entry.PrimaryWinsServer.IpAddress.Address );

         Console.WriteLine( "Secondary WINS Server: {0}", entry.SecondaryWinsServer.IpAddress.Address );

     while( pEntry != IntPtr.Zero );

     Marshal.FreeHGlobal(pArray);

   else

     Marshal.FreeHGlobal(pArray);

     throw new InvalidOperationException( "GetAdaptersInfo failed: " + ret );

GetAdaptersInfo returns a pointer to an IP_ADAPTER_INFO linked list.

In .NET 2.0, this library (The IP Helper API) is encapsulated in the NetworkInformation namespace.

Does this requiere a new dll?

[DllImport("iphlpapi.dll", SetLastError=true)]

Declare Function GetBestInterface Lib "iphlpapi.dll" (TODO) As TODO

DestAddr is a 32 bit representation of the four IP bytes. For .NET 1.0, you can get this from IPAddress.Address. In .NET 1.1, this is obsolete. You can use BitConverter.ToUInt32(IPAddress.GetAddressBytes()) instead.

Sample Code:

    public static class Win32ApiCalls

    [DllImport("iphlpapi.dll", CharSet = CharSet.Auto)]

    public static extern int GetBestInterface(UInt32 destAddr, out UInt32 bestIfIndex);

    class Program

        Console.WriteLine("Host name : " + hostInfo.HostName);

        Console.WriteLine("\r\nAliases : ");

        foreach (var thisAlias in hostInfo.Aliases)

            Console.WriteLine(thisAlias);

        Console.WriteLine("\r\nIP Address list :");

        foreach (var thisAddress in hostInfo.AddressList)

            Console.WriteLine(thisAddress);

        IPAddress ipv4Address = (from thisAddress in hostInfo.AddressList

                     where thisAddress.AddressFamily == AddressFamily.InterNetwork

                     select thisAddress).FirstOrDefault();

        if (ipv4Address == null)

            Console.WriteLine("No Ipv4 address found for www.yahoo.com.");

        Console.WriteLine("\r\nGetting best interface to reach {0}...", ipv4Address);

        int result = Win32ApiCalls.GetBestInterface(ipv4AddressAsUInt32, out interfaceindex);

        if (result != 0)

            throw new Win32Exception(result);

        Console.WriteLine("Best interface:\r\n" +

        Console.WriteLine("SocketException caught!!!");

        Console.WriteLine("Source : " + e.Source);

        Console.WriteLine("Message : " + e.Message);

        catch (ArgumentNullException e)

        Console.WriteLine("ArgumentNullException caught!!!");

        Console.WriteLine("Source : " + e.Source);

        Console.WriteLine("Message : " + e.Message);

        catch (NullReferenceException e)

        Console.WriteLine("NullReferenceException caught!!!");

        Console.WriteLine("Source : " + e.Source);

        Console.WriteLine("Message : " + e.Message);

        Console.WriteLine("Win32Exception caught!!!");

        Console.WriteLine("Source : " + e.Source);

        Console.WriteLine("Message : " + e.Message);

        Console.WriteLine("Exception caught!!!");

        Console.WriteLine("Source : " + e.Source);

        Console.WriteLine("Message : " + e.Message);

        // Search in all network interfaces that support IPv4.

        NetworkInterface ipv4Interface = (from thisInterface in NetworkInterface.GetAllNetworkInterfaces()

                          let ipv4Properties = thisInterface.GetIPProperties().GetIPv4Properties()

                          where ipv4Properties != null && ipv4Properties.Index == index

                          select thisInterface).SingleOrDefault();

        if (ipv4Interface != null)

        // Search in all network interfaces that support IPv6.

        NetworkInterface ipv6Interface = (from thisInterface in NetworkInterface.GetAllNetworkInterfaces()

                          let ipv6Properties = thisInterface.GetIPProperties().GetIPv6Properties()

                          where ipv6Properties != null && ipv6Properties.Index == index

                          select thisInterface).SingleOrDefault();

Alternative Managed API:

Do you know one? Please contribute it!

[DllImport("iphlpapi.dll", SetLastError=true)]

static extern uint GetExtendedTcpTable(IntPtr pTcpTable, ref int dwOutBufLen, bool sort, int ipVersion, TCP_TABLE_CLASS tblClass,uint reserved = 0);

<DllImport("iphlpapi.dll", SetLastError:=True)> _

Public Shared Function GetExtendedTcpTable(ByVal pTcpTable As IntPtr, ByRef dwOutBufLen As Integer, ByVal sort As Boolean, ByVal ipVersion As  Integer, ByVal tblClass As TCP_TABLE_CLASS, ByVal reserved As Integer) As UInteger

TCP_TABLE_CLASS

When you do not need the PID information look at: IPGlobalProperties.GetActiveTcpListeners Method from the System.Net.NetworkInformation namespace

(Msdn: http://msdn.microsoft.com/en-us/library/system.net.networkinformation.ipglobalproperties.getactivetcplisteners.aspx)

Sample Code:

Generic methods for IPv4 and IPv6. Using MIB_TCPROW_OWNER_PID, MIB_TCPTABLE_OWNER_PID, MIB_TCP6ROW_OWNER_PID, MIB_TCP6TABLE_OWNER_PID and TCP_TABLE_CLASS

public const int AF_INET = 2;    // IP_v4 = System.Net.Sockets.AddressFamily.InterNetwork

public const int AF_INET6 = 23;  // IP_v6 = System.Net.Sockets.AddressFamily.InterNetworkV6

public static List<MIB_TCPROW_OWNER_PID> GetAllTCPConnections()

    return GetTCPConnections<MIB_TCPROW_OWNER_PID, MIB_TCPTABLE_OWNER_PID>(AF_INET);

public static List<MIB_TCP6ROW_OWNER_PID> GetAllTCPv6Connections()

    return GetTCPConnections<MIB_TCP6ROW_OWNER_PID, MIB_TCP6TABLE_OWNER_PID>(AF_INET6);

private static List<IPR> GetTCPConnections<IPR, IPT>(int ipVersion)//IPR = Row Type, IPT = Table Type

    IPR[] tableRows;

    var dwNumEntriesField = typeof(IPT).GetField("dwNumEntries");

    uint ret = GetExtendedTcpTable(IntPtr.Zero, ref buffSize, true, ipVersion, TCP_TABLE_CLASS.TCP_TABLE_OWNER_PID_ALL);

    IntPtr tcpTablePtr = Marshal.AllocHGlobal(buffSize);

        ret = GetExtendedTcpTable(tcpTablePtr, ref buffSize, true, ipVersion, TCP_TABLE_CLASS.TCP_TABLE_OWNER_PID_ALL);

            return new List<IPR>();

        // get the number of entries in the table

        IPT table = (IPT)Marshal.PtrToStructure(tcpTablePtr, typeof(IPT));

        int rowStructSize = Marshal.SizeOf(typeof(IPR));

        uint numEntries = (uint)dwNumEntriesField.GetValue(table);

        // buffer we will be returning

        tableRows = new IPR[numEntries];

        IntPtr rowPtr = (IntPtr)((long)tcpTablePtr + 4);

            IPR tcpRow = (IPR)Marshal.PtrToStructure(rowPtr, typeof(IPR));

            tableRows[i] = tcpRow;

            rowPtr = (IntPtr)((long)rowPtr + rowStructSize);   // next entry

    finally

        Marshal.FreeHGlobal(tcpTablePtr);

    return tableRows != null ? tableRows.ToList() : new List<IPR>();

Sample Code:

Previous sample

public MIB_TCPROW_OWNER_PID[] GetAllTcpConnections()

    MIB_TCPROW_OWNER_PID[] tTable;

    uint ret = GetExtendedTcpTable(IntPtr.Zero, ref buffSize, true, AF_INET, TCP_TABLE_CLASS.TCP_TABLE_OWNER_PID_ALL);        

    IntPtr buffTable = Marshal.AllocHGlobal(buffSize);

        ret = GetExtendedTcpTable(buffTable, ref buffSize, true, AF_INET, TCP_TABLE_CLASS.TCP_TABLE_OWNER_PID_ALL);

            return null;

        // get the number of entries in the table

        MIB_TCPTABLE_OWNER_PID tab = (MIB_TCPTABLE_OWNER_PID)Marshal.PtrToStructure(buffTable, typeof(MIB_TCPTABLE_OWNER_PID));

        IntPtr rowPtr = (IntPtr)((long)buffTable + Marshal.SizeOf(tab.dwNumEntries));

        tTable = new MIB_TCPROW_OWNER_PID[tab.dwNumEntries];

            MIB_TCPROW_OWNER_PID tcpRow = (MIB_TCPROW_OWNER_PID)Marshal.PtrToStructure(rowPtr, typeof(MIB_TCPROW_OWNER_PID));

            tTable[i] = tcpRow;

            rowPtr = (IntPtr)((long)rowPtr + Marshal.SizeOf(tcpRow));   // next entry

    finally

        Marshal.FreeHGlobal(buffTable);

    return tTable;

PowerShell

  using System.Collections;

  using System.Collections.Generic;

  using System.Linq;

  // https://msdn2.microsoft.com/en-us/library/aa366073.aspx

  namespace IPHelper {

      // https://msdn2.microsoft.com/en-us/library/aa366913.aspx

      [StructLayout(LayoutKind.Sequential)]

      public struct MIB_TCPROW_OWNER_PID {

      public uint state;

      public uint localAddr;

      [MarshalAs(UnmanagedType.ByValArray, SizeConst = 4)]

      public byte[] localPort;

      public uint remoteAddr;

      [MarshalAs(UnmanagedType.ByValArray, SizeConst = 4)]

      public byte[] remotePort;

      public uint owningPid;

      // https://msdn2.microsoft.com/en-us/library/aa366921.aspx

      [StructLayout(LayoutKind.Sequential)]

      public struct MIB_TCPTABLE_OWNER_PID {

      public uint dwNumEntries;

      [MarshalAs(UnmanagedType.ByValArray, ArraySubType = UnmanagedType.Struct, SizeConst = 1)]

      public MIB_TCPROW_OWNER_PID[] table;

      // https://msdn.microsoft.com/en-us/library/aa366896

      [StructLayout(LayoutKind.Sequential)]

      public struct MIB_TCP6ROW_OWNER_PID {

      [MarshalAs(UnmanagedType.ByValArray, SizeConst = 16)]

      public byte[] localAddr;

      public uint localScopeId;

      [MarshalAs(UnmanagedType.ByValArray, SizeConst = 4)]

      public byte[] localPort;

      [MarshalAs(UnmanagedType.ByValArray, SizeConst = 16)]

      public byte[] remoteAddr;

      public uint remoteScopeId;

      [MarshalAs(UnmanagedType.ByValArray, SizeConst = 4)]

      public byte[] remotePort;

      public uint state;

      public uint owningPid;

      // https://msdn.microsoft.com/en-us/library/windows/desktop/aa366905

      [StructLayout(LayoutKind.Sequential)]

      public struct MIB_TCP6TABLE_OWNER_PID {

     public uint dwNumEntries;

     [MarshalAs(UnmanagedType.ByValArray, ArraySubType = UnmanagedType.Struct, SizeConst = 1)]

     public MIB_TCP6ROW_OWNER_PID[] table;

      // https://msdn2.microsoft.com/en-us/library/aa366386.aspx

      public enum TCP_TABLE_CLASS {

      TCP_TABLE_BASIC_LISTENER,

      TCP_TABLE_BASIC_CONNECTIONS,

      TCP_TABLE_BASIC_ALL,

      TCP_TABLE_OWNER_PID_LISTENER,

      TCP_TABLE_OWNER_PID_CONNECTIONS,

      TCP_TABLE_OWNER_PID_ALL,

      TCP_TABLE_OWNER_MODULE_LISTENER,

      TCP_TABLE_OWNER_MODULE_CONNECTIONS,

      TCP_TABLE_OWNER_MODULE_ALL

      // https://msdn.microsoft.com/en-us/library/aa366896.aspx

      public enum MIB_TCP_STATE {

      MIB_TCP_STATE_CLOSED,

      MIB_TCP_STATE_LISTEN,

      MIB_TCP_STATE_CLOSE_WAIT,

      MIB_TCP_STATE_CLOSING,

      MIB_TCP_STATE_LAST_ACK,

      MIB_TCP_STATE_DELETE_TCB

      public static class IPHelperAPI {

      [DllImport("iphlpapi.dll", SetLastError = true)]

      internal static extern uint GetExtendedTcpTable(

          IntPtr tcpTable,

          ref int tcpTableLength,

          bool sort,

          TCP_TABLE_CLASS tcpTableType,

      public class IPHelperWrapper : IDisposable {

      public const int AF_INET = 2;    // IP_v4 = System.Net.Sockets.AddressFamily.InterNetwork

      public const int AF_INET6 = 23;  // IP_v6 = System.Net.Sockets.AddressFamily.InterNetworkV6

      // Creates a new wrapper for the local machine

      public IPHelperWrapper() { }

      public void Dispose() { GC.SuppressFinalize(this); }

      public List<MIB_TCPROW_OWNER_PID> GetAllTCPv4Connections() {

          return GetTCPConnections<MIB_TCPROW_OWNER_PID, MIB_TCPTABLE_OWNER_PID>(AF_INET);

      public List<MIB_TCP6ROW_OWNER_PID> GetAllTCPv6Connections() {

          return GetTCPConnections<MIB_TCP6ROW_OWNER_PID, MIB_TCP6TABLE_OWNER_PID>(AF_INET6);

      public List<IPR> GetTCPConnections<IPR, IPT>(int ipVersion) { //IPR = Row Type, IPT = Table Type

          IPR[] tableRows;

          var dwNumEntriesField = typeof(IPT).GetField("dwNumEntries");

          uint ret = IPHelperAPI.GetExtendedTcpTable(IntPtr.Zero, ref buffSize, true, ipVersion, TCP_TABLE_CLASS.TCP_TABLE_OWNER_PID_ALL);

          IntPtr tcpTablePtr = Marshal.AllocHGlobal(buffSize);

          ret = IPHelperAPI.GetExtendedTcpTable(tcpTablePtr, ref buffSize, true, ipVersion, TCP_TABLE_CLASS.TCP_TABLE_OWNER_PID_ALL);

          if (ret != 0) return new List<IPR>();

          // get the number of entries in the table

          IPT table = (IPT)Marshal.PtrToStructure(tcpTablePtr, typeof(IPT));

          int rowStructSize = Marshal.SizeOf(typeof(IPR));

          uint numEntries = (uint)dwNumEntriesField.GetValue(table);

          // buffer we will be returning

          tableRows = new IPR[numEntries];

          IntPtr rowPtr = (IntPtr)((long)tcpTablePtr + 4);

              IPR tcpRow = (IPR)Marshal.PtrToStructure(rowPtr, typeof(IPR));

              tableRows[i] = tcpRow;

              rowPtr = (IntPtr)((long)rowPtr + rowStructSize);   // next entry

          finally {

          Marshal.FreeHGlobal(tcpTablePtr);

          return tableRows != null ? tableRows.ToList() : new List<IPR>();

      ~IPHelperWrapper() { Dispose(); }

      } // wrapper class

  Add-Type -TypeDefinition $TypeDefinition -PassThru | Out-Null

    $x=New-Object IPHelper.IPHelperWrapper

    $y=$x.GetAllTCPv4Connections()

    $services=Get-WmiObject -Namespace "root\cimv2" -Class "Win32_Service"

    $StateList=@("UNKNOWN","CLOSED","LISTEN","SYN-SENT","SYN-RECEIVED","ESTABLISHED","FIN-WAIT-1","FIN-WAIT-2","CLOSE-WAIT","CLOSING","LAST-ACK","TIME-WAIT","DELETE-TCB")

    for ($i=0; $i -lt $y.Count; $i++) {

      Add-Member -InputObject $objOutput -MemberType NoteProperty -Name "LocalAddress" -Value ([System.Net.IPAddress]::new($y[$i].localAddr).IPAddressToString)

      Add-Member -InputObject $objOutput -MemberType NoteProperty -Name "RemoteAddress" -Value ([System.Net.IPAddress]::new($y[$i].remoteAddr).IPAddressToString)

      Add-Member -InputObject $objOutput -MemberType NoteProperty -Name "LocalPort" -Value ($y[$i].localPort[1]+($y[$i].localPort[0]*0x100)+($y[$i].localPort[3]*0x1000)+($y[$i].localPort[2]*0x10000))

      Add-Member -InputObject $objOutput -MemberType NoteProperty -Name "RemotePort" -Value ($y[$i].remotePort[1]+($y[$i].remotePort[0]*0x100)+($y[$i].remotePort[3]*0x1000)+($y[$i].remotePort[2]*0x10000))

      Add-Member -InputObject $objOutput -MemberType NoteProperty -Name "PID" -Value $y[$i].owningPid

      Add-Member -InputObject $objOutput -MemberType NoteProperty -Name "ProcessName" -Value ((Get-Process -Id $y[$i].owningPid).ProcessName)

      Add-Member -InputObject $objOutput -MemberType NoteProperty -Name "StateValue" -Value $y[$i].state

      Add-Member -InputObject $objOutput -MemberType NoteProperty -Name "State" -Value $StateList[$y[$i].state]

      $boolNoService=$true

      for ($j=0; $j -lt $services.Count; $j++) {

      Add-Member -InputObject $objOutput -MemberType NoteProperty -Name "ServiceName" -Value $services[$j].Caption

      $boolNoService=$false

      if ($boolNoService) { Add-Member -InputObject $objOutput -MemberType NoteProperty -Name "ServiceName" -Value $null }

    /// <param name="pIfTable">A pointer to a buffer that receives the interface table as a MIB_IFTABLE structure</param>

    /// On input, specifies the size in bytes of the buffer pointed to by the pIfTable parameter.

    /// On output, if the buffer is not large enough to hold the returned interface table,

    ///  the function sets this parameter equal to the required buffer size in bytes

    /// sort the table by index

    /// A Boolean value that specifies whether the returned interface table should be sorted

    /// in ascending order by interface index. If this parameter is TRUE, the table is sorted.

    /// If the function succeeds, the return value is

    [DllImport("Iphlpapi.dll", SetLastError=true)]

    public static extern uint GetIfTable(IntPtr pIfTable, ref uint pdwSize, bool bOrder);

Declare Function GetIfTable Lib "iphlpapi.dll" (TODO) As TODO

Alternative Managed API:

System.Net.NetworkInformation.NetworkInterface.GetAllNetworkInterfaces()

Get if Table Wrapper Class

    /// Wrapper to unmanaged code. to use all in C# declarations

    public class IPHelperWrapper

    #region  fields

    /// MIB_IFROW Declaration

    protected static IPHelperTraslation.MIB_IFROW netWorkInfoBlock;

    public static IPHelperTraslation.MIB_IFROW[] mRows;

    /// each network comes in a row. See MIB_IFROW in IPHelper Traslation for more

    public static IPHelperTraslation.MIB_IFROW[] GetNetworkInterfaceBlock()

        IPHelperTraslation.GetIfTable(IntPtr.Zero, ref size, false);

        IntPtr buf = Marshal.AllocHGlobal((int)size);

        IPHelperTraslation.GetIfTable(buf, ref size, false);

        int numEntries = Marshal.ReadInt32(buf);

        mRows = new IPHelperTraslation.MIB_IFROW[numEntries];

        mRows[i] = (IPHelperTraslation.MIB_IFROW)Marshal.PtrToStructure((IntPtr)pRows, typeof(IPHelperTraslation.MIB_IFROW));

        pRows += Marshal.SizeOf(typeof(IPHelperTraslation.MIB_IFROW));

        Marshal.FreeHGlobal(buf);

[DllImport("Iphlpapi.dll", CharSet = CharSet.Auto)]

public static extern int GetInterfaceInfo(Byte[] PIfTableBuffer, ref int size);

Alternative Managed API:

Do you know one? Please contribute it!

Please add some!

Sample Code:

The following C# sourcecode implements classes and structures with the purpose of making the use of GetInterfaceInfo and IpReleaseAddress easier. Thanks to Lieutenant (http://www.red-gate.com/MessageBoard/viewtopic.php?t=5754) for submitting this code.

    [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]

    public struct IP_ADAPTER_INDEX_MAP

        public int Index;

        [MarshalAs(UnmanagedType.ByValTStr, SizeConst = PInvokes.MAX_ADAPTER_NAME)]

        public String Name;

    [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]

    public struct IP_INTERFACE_INFO

        public int NumAdapters;

        public IP_ADAPTER_INDEX_MAP[] Adapter;

        public static IP_INTERFACE_INFO FromByteArray(Byte[] buffer)

            Marshal.Copy(buffer, 0, new IntPtr(&iNumAdapters), 4);

            IntPtr ptr = Marshal.AllocHGlobal(Marshal.SizeOf(map));

            Marshal.StructureToPtr(map, ptr, false);

            Marshal.Copy(buffer, offset, ptr, Marshal.SizeOf(map));

            map = (IP_ADAPTER_INDEX_MAP)Marshal.PtrToStructure(ptr, typeof(IP_ADAPTER_INDEX_MAP));

            Marshal.FreeHGlobal(ptr);

            offset += Marshal.SizeOf(map);

    internal class PInvokes

        public const int MAX_ADAPTER_NAME = 128;

        public const int ERROR_INSUFFICIENT_BUFFER = 122;

        public const int ERROR_SUCCESS = 0;

        [DllImport("Iphlpapi.dll", CharSet = CharSet.Auto)]

        public static extern int GetInterfaceInfo(Byte[] PIfTableBuffer, ref int size);

        [DllImport("Iphlpapi.dll", CharSet = CharSet.Auto)]

        public static extern int IpReleaseAddress(ref IP_ADAPTER_INDEX_MAP AdapterInfo);

    public class Iphlpapi

        public static IP_INTERFACE_INFO GetInterfaceInfo()

        int r = PInvokes.GetInterfaceInfo(null, ref size);

        public static bool IpReleaseAddress(IP_ADAPTER_INDEX_MAP adapter)

        if (PInvokes.IpReleaseAddress(ref adapter) == PInvokes.ERROR_SUCCESS)

        else

            return false;

        public static void IpReleaseAllAddresses()

            IpReleaseAddress(info.Adapter[i]);

[DllImport("iphlpapi.dll", SetLastError=true)]

public static extern int GetIpAddrTable(IntPtr pIpAddrTable, ref int pdwSize, bool bOrder);

Declare Ansi Function

GetIpAddrTable Lib "iphlpapi.dll" (ByRef ipTable As IntPtr, ByRef tableSize As IntPtr, ByVal ordered As Boolean) As UInt32

[DllImport(S"IPHLPAPI.DLL", EntryPoint=S"GetIpAddrTable", SetLastError=true, CharSet=CharSet::Unicode, ExactSpelling=true)]

static UInt32 GetIpAddressTable( [Out] IntPtr ipTable, [In,Out] IntPtr tableSize, bool sort);

Alternative Managed API:

Example:

    Console.WriteLine(strIP.ToString());

Please add some!

Sample Code:

GetIpAddrTable( IntPtr.Zero, ref nBufSize, false );

// allocate the buffer

pBuf = Marshal.AllocHGlobal( nBufSize );

int r = GetIpAddrTable( pBuf, ref nBufSize, false );

    throw new System.ComponentModel.Win32Exception( r );

int entrySize = Marshal.SizeOf(typeof(MIB_IPADDRROW));

int nEntries = Marshal.ReadInt32(pBuf);

int tableStartAddr = (int)pBuf + sizeof(int);

    IntPtr pEntry = (IntPtr)(tableStartAddr + i * entrySize);

    MIB_IPADDRROW addrStruct = (MIB_IPADDRROW)Marshal.PtrToStructure(pEntry, typeof(MIB_IPADDRROW));

    Marshal.FreeHGlobal( pBuf );

// helper function IPToString

[DllImport("iphlpapi.dll", EntryPoint="GetIpNetTable")]

static extern int GetIpNetTable(IntPtr pIpNetTable, ref int pdwSize, bool bOrder);

    <DllImport("IpHlpApi.dll")>

    Private Shared Function GetIpNetTable(pIpNetTable As IntPtr, <MarshalAs(UnmanagedType.U4)> ByRef pdwSize As Integer, bOrder As Boolean) As <MarshalAs(UnmanagedType.U4)> Integer

    [StructLayout(LayoutKind.Sequential)]    

        [MarshalAs(UnmanagedType.U4)]    

        public uint dwIndex;    

        [MarshalAs(UnmanagedType.U4)]    

        public uint dwPhysAddrLen;    

        [MarshalAs(UnmanagedType.U1)]    

        public byte mac0;    

        [MarshalAs(UnmanagedType.U1)]    

        public byte mac1;    

        [MarshalAs(UnmanagedType.U1)]    

        public byte mac2;    

        [MarshalAs(UnmanagedType.U1)]    

        public byte mac3;    

        [MarshalAs(UnmanagedType.U1)]    

        public byte mac4;    

        [MarshalAs(UnmanagedType.U1)]    

        public byte mac5;    

        [MarshalAs(UnmanagedType.U1)]    

        public byte mac6;    

        [MarshalAs(UnmanagedType.U1)]    

        public byte mac7;    

        [MarshalAs(UnmanagedType.U4)]    

        public uint dwAddr;    

        [MarshalAs(UnmanagedType.U4)]    

        public uint dwType;      

    Public Const ERROR_SUCCESS As Integer = 0

    Public Const ERROR_INSUFFICIENT_BUFFER As Integer = 122

<StructLayout(LayoutKind.Sequential)>

Public Structure MIB_IPNETROW

    <MarshalAs(UnmanagedType.U4)>

    Public dwIndex As UInteger

    <MarshalAs(UnmanagedType.U4)>

    Public dwPhysAddrLen As UInteger

    <MarshalAs(UnmanagedType.ByValArray, SizeConst:=6)>

    Public bPhysAddr() As Byte

    <MarshalAs(UnmanagedType.U4)>

    Public dwAddr As UInteger

    <MarshalAs(UnmanagedType.U4)>

    Public dwType As DWTYPES

Public Enum DWTYPES As UInteger

    <MarshalAs(UnmanagedType.U4)>

    <MarshalAs(UnmanagedType.U4)>

    Invalid = 2

    <MarshalAs(UnmanagedType.U4)>

    <MarshalAs(UnmanagedType.U4)>

Alternative Managed API:

Do you know one? Please contribute it!

If you are only interesting in getting the mac Address and you are deploying to Windows 2008 or later, you might want to use ResolveIpNetEntry2 (http://msdn.microsoft.com/en-us/library/aa814455(VS.85).aspx) instead.

Please add some!

C# Sample Code:

    //http://stackoverflow.com/questions/1148778/how-do-i-access-arp-protocol-information-through-c-net

    using System.ComponentModel;

    namespace GetIpNetTable

    class Program   {      

        // The max number of physical addresses.      

        const int MAXLEN_PHYSADDR = 8;      

          // Declare the GetIpNetTable function.

          [DllImport("IpHlpApi.dll")]

          [return: MarshalAs(UnmanagedType.U4)]

          static extern int GetIpNetTable(

         IntPtr pIpNetTable,

         [MarshalAs(UnmanagedType.U4)]

         bool bOrder);

         // The result from the API call.

         int result = GetIpNetTable(IntPtr.Zero, ref bytesNeeded, false);

         // Call the function, expecting an insufficient buffer.

         if (result != ERROR_INSUFFICIENT_BUFFER)

            throw new Win32Exception(result);

         // Allocate the memory, do it in a try/finally block, to ensure

         // that it is released.

         // Try/finally.

            // Allocate the memory.

            buffer = Marshal.AllocCoTaskMem(bytesNeeded);

            // Make the call again. If it did not succeed, then

            result = GetIpNetTable(buffer, ref bytesNeeded, false);

            // If the result is not 0 (no error), then throw an exception.

            if (result != 0)

               throw new Win32Exception(result);

            // Now we have the buffer, we have to marshal it. We can read

            // the first 4 bytes to get the length of the buffer.

            int entries = Marshal.ReadInt32(buffer);

               Marshal.SizeOf(typeof(int)));    

            // Allocate an array of entries.

            MIB_IPNETROW[] table = new MIB_IPNETROW[entries];

            // Cycle through the entries.

               // Call PtrToStructure, getting the structure information.

               table[index] = (MIB_IPNETROW) Marshal.PtrToStructure(new

              Marshal.SizeOf(typeof(MIB_IPNETROW)))), typeof(MIB_IPNETROW));

               IPAddress ip=new IPAddress(table[index].dwAddr);

               Console.Write("IP:"+ip.ToString()+"\t\tMAC:");

               b=table[index].mac0;

              Console.Write("0");

               else

              Console.Write("");

               Console.Write(b.ToString("X"));

               b=table[index].mac1;

              Console.Write("-0");

               else

              Console.Write("-");

               Console.Write(b.ToString("X"));

               b=table[index].mac2;

              Console.Write("-0");

               else

              Console.Write("-");

               Console.Write(b.ToString("X"));

               b=table[index].mac3;

              Console.Write("-0");

               else

              Console.Write("-");

               Console.Write(b.ToString("X"));

               b=table[index].mac4;

              Console.Write("-0");

               else

              Console.Write("-");

               Console.Write(b.ToString("X"));

               b=table[index].mac5;

              Console.Write("-0");

               else

              Console.Write("-");

               Console.Write(b.ToString("X"));

               Console.WriteLine();

         finally

            // Release the memory.

            Marshal.FreeCoTaskMem(buffer);

VB.NET Sample Code:

    Public Shared Sub GetARPTablr()

    ' The result from the API call.

    Dim result As Integer = GetIpNetTable(IntPtr.Zero, bytesNeeded, False)

    ' Call the function, expecting an insufficient buffer.

    If result <> ERROR_INSUFFICIENT_BUFFER Then

        Throw New Win32Exception(result)

    ' Allocate the memory, do it in a try/finally block, to ensure

    ' that it is released.

    ' Try/finally.

        ' Allocate the memory.

        buffer = Marshal.AllocCoTaskMem(bytesNeeded)

        ' Make the call again. If it did not succeed, then

        result = GetIpNetTable(buffer, bytesNeeded, False)

        ' If the result is not 0 (no error), then throw an exception.

        If result <> ERROR_SUCCESS Then

        Throw New Win32Exception(result)

        ' Now we have the buffer, we have to marshal it. We can read

        ' the first 4 bytes to get the length of the buffer.

        Dim entries As Integer = Marshal.ReadInt32(buffer)

        Dim currentBuffer As New IntPtr(buffer.ToInt64() + Marshal.SizeOf(GetType(Integer)))

        ' Allocate an array of entries.

        Dim table As MIB_IPNETROW() = New MIB_IPNETROW(entries - 1) {}

        ' Cycle through the entries.

        ' Call PtrToStructure, getting the structure information.

        table(index) = DirectCast(Marshal.PtrToStructure(New IntPtr(currentBuffer.ToInt64() + (index * Marshal.SizeOf(GetType(MIB_IPNETROW)))), GetType(MIB_IPNETROW)), MIB_IPNETROW)

        If table(index).dwType <> DWTYPES.Invalid And table(index).dwType <> DWTYPES.Other Then

            Dim ip As New IPAddress(table(index).dwAddr)

            Dim mac As New PhysicalAddress(table(index).bPhysAddr)

            Console.WriteLine(table(index).dwType.ToString & vbTab & vbTab & "IP:" + ip.ToString() & vbTab & vbTab & "MAC: " & MACtoString(mac))

    Finally

        ' Release the memory.

        Marshal.FreeCoTaskMem(buffer)

        '  Marshal.FreeHGlobal(rowptr)

    Public Shared Function MACtoString(mac As PhysicalAddress, Optional Capital As Boolean = True) As String

    If Capital Then ' In capital Letters

        Return String.Join(":", (From z As Byte In mac.GetAddressBytes Select z.ToString("X2")).ToArray())

    Else

        Return String.Join(":", (From z As Byte In mac.GetAddressBytes Select z.ToString("x2")).ToArray())

[DllImport("iphlpapi.dll", CharSet=CharSet.Ansi)]

public static extern int GetNetworkParams(IntPtr pFixedInfo, ref UInt32 pBufOutLen);

    <DllImport("iphlpapi.dll", CharSet:=CharSet.Ansi)>

    Public Shared Function GetNetworkParams(pFixedInfo As IntPtr, ByRef pBufOutLen As Integer) As Integer

Alternative Managed API:

Use [System.Net.NetworkInformation.IPGlobalProperties].GetIPGlobalProperties().

Note that ScopeId is renamed to DhcpScopeName and EnableProxy is renamed to IsWinsProxy.

Please add some!

Sample Code:

int infoLen = Marshal.SizeOf(typeof(FIXED_INFO));

while (true)

    infoPtr = Marshal.AllocHGlobal(Convert.ToInt32(infoLen));

    ret = GetNetworkParams(infoPtr, ref infoLen);

    if (ret == ERROR_BUFFER_OVERFLOW)

        Marshal.FreeHGlobal(infoPtr);

    throw new ApplicationException("An error occurred while fetching adapter information.", new Win32Exception(Convert.ToInt32(ret)));

FIXED_INFO info = (FIXED_INFO)Marshal.PtrToStructure(infoPtr, typeof(FIXED_INFO));

VB.NET Example

    Private Const ERROR_SUCCESS As Long = 0

    Private Const ERROR_BUFFER_OVERFLOW As Integer = 111

    Private Const MAX_HOSTNAME_LEN As Integer = 128

    Private Const MAX_SCOPE_ID_LEN As Integer = 256

    Private Const MAX_DOMAIN_NAME_LEN As Integer = 128

    <StructLayout(LayoutKind.Sequential, CharSet:=CharSet.Ansi)>

    <MarshalAs(UnmanagedType.ByValTStr, SizeConst:=MAX_HOSTNAME_LEN + 4)>

    Public HostName As String

    <MarshalAs(UnmanagedType.ByValTStr, SizeConst:=MAX_DOMAIN_NAME_LEN + 4)>

    Public DomainName As String

    Public CurrentDnsServer As IntPtr

    Public DnsServerList As IP_ADDR_STRING

    Public NodeType As UInteger

    <MarshalAs(UnmanagedType.ByValTStr, SizeConst:=MAX_SCOPE_ID_LEN + 4)>

    Public ScopeId As String

    Public EnableRouting As Boolean

    Public EnableProxy As Boolean

    Public EnableDns As Boolean

    <DllImport("iphlpapi.dll", CharSet:=CharSet.Ansi)>

    Private Shared Function GetNetworkParams(pFixedInfo As IntPtr, ByRef pBufOutLen As Integer) As Integer

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click

    Dim infoLen As Integer

    '      Dim bufOF As Boolean = True

        '       Do While bufOF

        ret = GetNetworkParams(infoPtr, infoLen)

        If ret = ERROR_BUFFER_OVERFLOW Then

        infoPtr = Marshal.AllocHGlobal(infoLen)

        ret = GetNetworkParams(infoPtr, infoLen)

        If ret = ERROR_BUFFER_OVERFLOW Then

        ElseIf ret = ERROR_SUCCESS Then

        Dim info As FIXED_INFO = Marshal.PtrToStructure(infoPtr, GetType(FIXED_INFO))

        ' We can now access the FIXED_INFO fields here.

        Console.WriteLine("Enable Routing: {0}", info.EnableRouting) ' CBool(info.EnableRouting))

        Else

            Console.WriteLine("Error {0}", errorMessage)

        '   Loop

        Console.WriteLine(ex.ToString)

    Finally

        Marshal.FreeHGlobal(infoPtr)

[DllImport("iphlpapi.dll", SetLastError=true)]

Declare Function IPAddress Lib "iphlpapi.dll" (TODO) As TODO

Please add some!

Sample Code:

Please add some!

Alternative Managed API:

Do you know one? Please contribute it!

    [DllImport("Iphlpapi.dll", CharSet = CharSet.Auto)]

    public static extern int IpReleaseAddress(ref IP_ADAPTER_INDEX_MAP AdapterInfo);

Alternative Managed API:

Do you know one? Please contribute it!

Please add some!

Sample Code:

The following C# sourcecode implements classes and structures with the purpose of making the use of GetInterfaceInfo and IpReleaseAddress easier. Thanks to Lieutenant (http://www.red-gate.com/MessageBoard/viewtopic.php?t=5754) for submitting this code.

    [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]

    public struct IP_ADAPTER_INDEX_MAP

    public int Index;

    [MarshalAs(UnmanagedType.ByValTStr, SizeConst = PInvokes.MAX_ADAPTER_NAME)]

    public String Name;

    [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]

    public struct IP_INTERFACE_INFO

    public int NumAdapters;

    public IP_ADAPTER_INDEX_MAP[] Adapter;

    public static IP_INTERFACE_INFO FromByteArray(Byte[] buffer)

        Marshal.Copy(buffer, 0, new IntPtr(&iNumAdapters), 4);

        IntPtr ptr = Marshal.AllocHGlobal(Marshal.SizeOf(map));

        Marshal.StructureToPtr(map, ptr, false);

        Marshal.Copy(buffer, offset, ptr, Marshal.SizeOf(map));

        map = (IP_ADAPTER_INDEX_MAP)Marshal.PtrToStructure(ptr, typeof(IP_ADAPTER_INDEX_MAP));

        Marshal.FreeHGlobal(ptr);

        offset += Marshal.SizeOf(map);

    internal class PInvokes

    public const int MAX_ADAPTER_NAME = 128;

    public const int ERROR_INSUFFICIENT_BUFFER = 122;

    public const int ERROR_SUCCESS = 0;

    [DllImport("Iphlpapi.dll", CharSet = CharSet.Auto)]

    public static extern int GetInterfaceInfo(Byte[] PIfTableBuffer, ref int size);

    [DllImport("Iphlpapi.dll", CharSet = CharSet.Auto)]

    public static extern int IpReleaseAddress(ref IP_ADAPTER_INDEX_MAP AdapterInfo);

    public class Iphlpapi

    public static IP_INTERFACE_INFO GetInterfaceInfo()

    int r = PInvokes.GetInterfaceInfo(null, ref size);

    public static bool IpReleaseAddress(IP_ADAPTER_INDEX_MAP adapter)

    if (PInvokes.IpReleaseAddress(ref adapter) == PInvokes.ERROR_SUCCESS)

    else

        return false;

    public static void IpReleaseAllAddresses()

        IpReleaseAddress(info.Adapter[i]);